title: Squaramide-catalyzed enantioselective Michael addition of masked acyl cyanides to substituted enones.
abstract: Masked acyl cyanide (MAC) reagents are shown to be effective umpolung synthons for enantioselective Michael addition to substituted enones. The reactions are catalyzed by chiral squaramides and afford adducts in high yields (90-99%) and with excellent enantioselectivities (85-98%). The addition products are unmasked to produce dicyanohydrins that, upon treatment with a variety of nucleophiles, provide γ-keto acids, esters, and amides. The use of this umpolung synthon has enabled, in enantiomerically enriched form, the first total synthesis of the prenylated phenol (+)-fornicin C.
authors.affiliation: Department of Chemistry, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Kin S
authors.initials: KS
authors.lastname: Yang
authors.forename: Antoinette E
authors.initials: AE
authors.lastname: Nibbs
authors.forename: Yunus E
authors.initials: YE
authors.lastname: Türkmen
authors.forename: Viresh H
authors.initials: VH
authors.lastname: Rawal
mesh_terms: D002384:Catalysis; D003486:Cyanides / Q000737:chemistry*; D003503:Cyclobutanes / Q000737:chemistry*; D005663:Furans / Q000737:chemistry; D032902:Ganoderma / Q000737:chemistry; D007202:Indicators and Reagents; D007659:Ketones / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D010636:Phenols / Q000737:chemistry; D013237:Stereoisomerism; D013449:Sulfonamides / Q000737:chemistry*
chemical_list: D003486:Cyanides; D003503:Cyclobutanes; D005663:Furans; D007202:Indicators and Reagents; D007659:Ketones; D010636:Phenols; D013449:Sulfonamides; C514412:fornicin C; C527748:squaric acid amide